Mouse Skills:Plague of Toads (Toad Affinity)
Firebomb (Flash Fires)
Hotbar Skills:Locust Swarm (Pestilence)
Hex (Hedge Magic)
Big Bad Voodoo (Jungle Drums)
Fetish Army (Devoted Following OR Legion of Daggers)
Passive Skills:Tribal Rites
Fetish Syncophants
Pierce the Veil
In this case, the first element to discuss are the cooldown skills. Big Bad Voodoo and Hex both summon Fetishes, though these ones don’t attack like the ones you’re getting from your other skills. Instead, they boost you and your party and debilitate your enemies, just to make things easier on your companions- and by companions, I mean ankle-biting demons. Fetish Army with Devoted Following should be able to be used virtually every fight, especially with Tribal Rites cutting its cooldown- and Big Bad Voodoo should be usable just about every other fight and last for most of the combat. By hitting Jungle Drums, then Devoted Following, and thirdly Hedge Magic, you can set things up to be especially easy for your Fetishes, as well as any other players who are in your party. If you find you enter fights less frequently than warrants the use of Devoted Following alongside Tribal Rites, you can use Legion of Daggers to get a larger number of Fetishes out of the skill instead of more frequent use.
Immediately after that, you want to lay in Locust Swarm, which is using the Pestilence rune here for the fastest possible spread- since you don’t directly control the Fetishes, you can’t decide which enemy they’re attacking. By using Pestilence, you make it much more likely that they will be hitting things affected by the Locust Swarm. After that, you can use Firebomb- which has Flash Fires to give it again, as many targets as possible even on a spread-out group of enemies. If you happen to run out of mana, then you switch over to Plague of Toads, which is free thanks to Toad Affinity- and both of your mouse skills have a chance to spawn Fetishes, so spamming them as much as possible will enable you to spawn the maximum number of Fetishes.
Fetish Syncophants works with your main recurring-use skills to give you plenty of extra Fetishes, and Tribal Rites is obviously present to accelerate your use of Fetish Army. Pierce the Veil is especially strong thanks to its damage increase, and since you have the free version of Plague of Toads you probably aren’t going to mind running out of Mana before you’re done Firebombing everything.
Curiously, this skill set works almost as well on single bosses, with the only difference being that you want to skip Firebomb in favor of Plague of Toads so that you can maintain the Pestilence damage on your enemy.